The overall goal of this Program Project is to study in detail some of those specific aspects of reproduction which occur between ovulation and implantation. Our explicit concern is with both the control of processes in which hormones of reproduction play an essential regulatory role and control of their synthesis, secretion, distribution and metabolism. Specific objectives relate to the control of uterine protein secretion by progesterone; the kinetics and subcellular distribution and influence of progesterone in the primate brain; the biosynthesis of estrogens in human tissues at the molecular level; the complex interaction of pituitary, decidual, and ovarian and placental hormones to influence ovarian progesterone secretion and implantation in the rat; and the relationship between ovarian blood flow and ovarian steroid secretion and hormonal control of motility of the oviduct. BIBLIOGRAPHIC REFERENCES: Little, B., R.B. Billiar, S.S. Rahman, W.A. Johnson, Y. Takaoka and R.J. White, In Vivo Aspects of Progesterone Distribution and Metabolism. American Journal Obstetrics and Gynecology 123:527, 1975. Rahman, S., R.B. Billiar and B. Little, Induction of uterogrobin in rabbits by progestogens, estradoil-17 beta, and ACTH, Biol. Reprod. 12:305, 1975.